A famous Broadway actress, Sally Ross, is enjoying a successful career and is beloved by fans everywhere. Among her admirers is Douglas Breen, an obsessed young man who believes he has a special connection with her. He sends her letters expressing his admiration, but when his attempts to make contact go unanswered, his infatuation quickly turns into a dangerous obsession. Douglas becomes fixated on inserting himself into Sally's life, convinced that she is ignoring him deliberately.

While Sally continues her professional and personal routines unaware of the extent of Douglas' fixation, Douglas' actions escalate from sending letters to disturbingly bold and violent attempts to get her attention. The increasingly menacing nature of his actions soon puts everyone close to Sally at risk. As the tension builds, Sally must confront the horrifying reality that her biggest fan has become her worst nightmare. What started as admiration spirals into a gripping psychological thriller where boundaries between adoration and obsession dangerously blur.